【Python】俄罗斯农夫算法

 

相关介绍百度

 

直接上代码：

方法1：pandas法

 

import pandas as pd

def half_double(n1, n2):
    halving = [n1]
    doubling = [n2]
    while min(halving) > 1:
        halving.append(math.floor(min(halving) / 2))
        doubling.append(max(doubling) * 2)
    half_double = pd.DataFrame(zip(halving, doubling))
    return half_double.loc[half_double[0] % 2 == 1, 1].sum()


n1, n2 = 123456789, 987654321
half_double(n1, n2)

8ms出来结果

 

 

方法2：Python移位法（更快，更强）

 

%%time
def RPM(a, b):
    p = 0
    while a and b:
        if (b & 1):  # b%2
            p += a
            a <<= 1
        else:
            a <<= 1
        b >>= 1
    return p


print(RPM(123456789, 987654321))
print(123456789 * 987654321)

4ms出结果